To provide good power transfer and minimize signal reflection between a transmission line and a receiver, the input impedance of the receiver is preferably matched to the impedance of the transmission line. In cases in which the impedance of the transmission is known in advance, the receiver can be designed to have its impedance match the impedance of the transmission line. However, in situations in which the impedance of the transmission line is not known, or in situations in which the receiver is to be used with transmission lines having different impedances, the receiver cannot be designed to have its input impedance match the impedance of the transmission line.
A need therefore exists for a termination matching circuit having an adjustable impedance that can be adjustably set according to the needs of a particular application.